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Comment by Rantenki | Hacker News Reader

This is fantastic news for virtualization:

1. Memory deduplication on kvm machines: matching memory pages are COWed. Hopefully there is a re-spin of the virtio drivers too (which rock, btw).

2. Way newer kvm/libvirt (the old ones sucked)

3. Python 2.6. They skipped 2.5 entirely, which is nice.

Just keep in mind, they'll be supporting it for a VERY long time, so RHEL6 will be looking pretty tired in another 3.5 years (the current age of RHEL5).

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I wonder, will I be able to use Xen on RHEL6 servers? Should I?

I'm learning to use virtualization and I picked Xen because seemed to me like solid technology - it's good for Amazon, Google and prgmr.com, so surely it will be good enough for me? On the other hand, it is not included in the kernel, its usage tends to lead to using anscient kernels, Red Hat and Ubuntu are moving away from it. I'm in doubt what virtualization technology should I be using.

The pv_ops patches are just starting to make it into mainline now, KVM's had quite a head start.

Xen is dead. KVM is now equally "solid", easier to use, better supported, etc.

libguestfs ... a proper way to access and edit disk images.

(I am the author)

Thanks for creating and putting so many hours into this library. I think this tool more than any other has allowed me to do so much with KVM.

is memory deduplication the KSM thingy released about a year ago?

http://git.kernel.org/?p=linux/kernel/git/stable/linux-2.6.3...

Yes. In fact KSM can be used on any Linux process although you have to mark the regions that can be merged with a special mmap flag. It works well with VMs because they basically mmap a huge chunk of sequential memory (for the VM's RAM) which is marked thus.

Edit: madvise, not mmap.

Yes.

It's too bad they didn't skip to Python 2.7 which seems that will be the last 2.x version [1].

[1] http://sayspy.blogspot.com/2010/10/viewing-python-32-as-succ...

I don't think 2.7 has been out nearly long enough for a Linux distro to be based on it. RHEL uses Python for core stuff like yum.

Fedora 14 uses it and they could have delayed the release.

You can always make the argument that you could delay the release of the distro to get "the next version of critical library/tool X", however, then you never release.

The most important feature is _SHIPPING_.

They already delayed the release by 2 years more than they should've.

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